It is proposed to substantially extend an investigation undertaken during the last five years on the response of a head/neck system to impact and impulsive loading by constructing a physical replica and a corresponding analytical model of the human head, neck, spinal column and the upper torso and to obtain and correlate the reponse of both systems to impact and impulsive loading at various positions of the configuration. This investigation will constitute a significant and important extension of an analogous experimental and theoretical study involving solely the head and neck which was regarded as rigidly fixed at the level of the third thoracic vertebra. The suggested augmenting of the scope will permit the assessment of the effect of the torso on both spinal and muscular deformation and the significance of such loading on the vital organs contained within this region. The techniques to be employed are those successfully utilized in the study of the two-component head-neck system and involve the simulation of all structural components by inanimate members, especially devised to resemble in shape and properties those of the living human, with the exception of the head, which will be represented by a fluid-filled skull with an outer layer resembling scalp and skin. The theoretical description will be provided by a lumped-parameter representation permitting three-dimensional motion of the system whose history can be determined relatively inexpensively on an intermediate-sized computer. The results of the proposed investigations will permit the delineation of the deformation and the loads exerted on critical parts of the human structure, providing an increased understanding of the response of these components to accidental external loading of various levels of severity. The validation of the numerical model upon comparison with data both from the inanimate replica to be tested and from experimental results on cadavers and animals available in the literature will generate a predictive tool capable of anticipating the deleterious effects to the human due to severe and traumatic blows and accelerations. This will not only substantially increase the anatomical knowledge of behavior under these circumstances, but will also delineate the regions of maximum danger, perhaps useful in diagnosis and treatment. Most importantly, however, this information will serve to increase the effectiveness of protective devices and environments designed to ameliorate the disabling features of such violent loading.